Conventional tank-type toilet used in households throughout North America were developed many years ago. The apparatus most commonly used to control the flushing cycle of these tanks consists of a flush valve connected to a lift arm. The flush valve has a built-in float, or positive buoyancy means, usually in the form of a styrofoam component or an air pocket, and is designed to have adequate buoyancy to remain open upon raising and releasing the lift arm until substantially all of the water contained in the flush tank is drained into the toilet bowl. As the water level in the toilet tank nears the bottom of the tank where the flush valve is located, the absence of adequate water in the tank causes the flush valve to lose its buoyancy. This enables the valve to reseal the toilet tank discharge opening, thus allowing the tank to refill via a separate refill mechanism. This relatively simple toilet tank design has proven commercially successful and reliable over the years, but suffers from a very serious drawback, i.e. regardless of need, a large volume of water (about 4 to 5 gallons) is used with each flush. This volume of water is particularly excessive when flushing liquid waste alone, or liquid waste accompanied by a small quantity of toilet tissue.
It is generally recognized that toilets account for a very significant component of water usage, particularly in metropolitan areas. According to the U.S. Department of Housing and Urban Development, toilets account for at least 40% of the water used in households. In recent years, because of increases in population density and the associated rise in demand for water, and because of limitations with regard to water supplies, severe water shortages have developed in some parts of the country and are anticipated in many others. Municipalities are struggling to keep up not only with the rising demand for water, but also with the corresponding need for costly additional water and sewerage treatment facilities.
There have been numerous devices proposed to reduce the amount of water used for flushing toilets. For example, U.S. Pat. No. 3,812,545 discloses a toilet tank flush valve with manually adjustable buoyancy. Since the lid of the toilet tank has to be removed in order to make the adjustment, there are serious operational drawbacks associated with the use of this valve.
U.S. Pat. No. 4,969,218 discloses a semi-flush kit employing two floats. Its design is very complex and appears to be of doubtful reliability and practicality.
U.S. Pat. Nos. 5,023,960 and 5,073,995 disclose water saver devices which cause the flapper valve in a conventional toilet tank to close prematurely. The designs of these devices are also quite complex and offer limited flexibility over the control of the volume of water used per flush.
U.S. Pat. No. 5,031,254 discloses a device that prevents automatic operation of a toilet tank and requires the user to keep the lift arm in an open position for the duration of the flush cycle. The device appears to be of limited practicality.
U.S. Pat. No. 5,042,096 provides a dual-level toilet flushing mechanism featuring an upper and a lower flapper valve activated by upward and downward, respectively, swivel action of the flush handle. The amount of water used per flush can be selected from only two predetermined volumes.
U.S. Pat. No. 5,070,547 provides a semi-flush retrofit kit that includes double flush handles, such that if one handle is pressed downward the toilet is flushed fully and if the other handle is pressed downward the toilet tank is only partially emptied. The kit appears very complex, and offers only two predetermined flush options--full and partial.
U.S. Pat. No. 5,070,548 discloses a toilet tank attachment for reducing the amount of water with which the toilet bowl is filled. With the attachment in place, the amount of water used per flush can not be varied.
U.S. Pat. No. 5,153,948 discloses a water saver unit which includes a flapper valve and a float positioned on the strap linking the flapper valve with the lift arm of the toilet tank. The unit is quite simple, but suffers from a very serious operational drawback. In order to change the amount of water used per flush, one has to lift the lid of the toilet tank and manually adjust the position of the float.
U.S. Pat. No. 5,157,796 discloses a double flush toilet apparatus which facilitates full or partial flushing of water from a toilet tank, but lacks convenient flexibility for adjusting the volume of water used during a partial flush.
Many of these patents served to further the understanding of problems associated with efforts to reduce water usage in conventional toilets. None, however, has suggested an apparatus that can be adjusted from outside of the tank to provide an infinite number of settings and yet be sufficiently simple, retrofitable, flexible, reliable and inexpensive to gain wide commercial acceptance.
In light of the foregoing, there still exists a need in the art for new methods of water conservation. There also exits a need for new technologies which will reduce per capita water consumption without water rationing or other unwarranted hardships.
It is, accordingly, an object of the present invention to provide an apparatus for controlling and reducing the volume of water used in flushing conventional toilets.
It is another object of the invention to provide an apparatus enabling one to control from outside the toilet tank the amount of water to be used when flushing the toilet.
It is a further object of this invention to provide a method for converting a conventional toilet tank which releases a large volume of water with each flush to a water saving toilet tank using the apparatus of this invention.
It is still another object of this invention to facilitate new toilet tank designs utilizing the water saving apparatus of this invention.
These and other objects of the invention will be apparent to those skilled in the art from the specification and attached drawings taken in their entirety.